Facile Functionalization of Polyethylene via Click Chemistry
(5659–5665) Macromolecules 44 #14 (2011)
Hong et al of the Chinese Academy of Science, China, synthesized a series of well-defined functional polyethylene graft copolymers with high molecular weights via the combination of ethylene/5-norbornene-2-methyl propargyl ether (NMPE) copolymerization using bis(β-enaminoketonato)titanium catalysts and following click coupling reaction.  Bis(β-enaminoketonato)titanium catalysts have been proved to be the potent catalysts for ethylene/NMPE copolymerization, producing high molecular weight copolymers with unimodal molecular weight distributions. 13C NMR (dept) and 1H NMR spectra reveal the copolymerization proceeds in a regioselective way with alkynyl group retained near the main chain. The following click coupling reactions between ethylene/NMPE copolymer and azido-terminated polymer (PEO–N3, PS–N3) have been achieved under mild conditions independent of the chemical structure and molecular weight of azido-terminated polymer, providing functional polyethylene with well-defined structure and high molecular weight.  (RDC 7/20/20110